Methods for distributing password-protected content files are well known. Common example of such content files are .pdf files, Microsoft Word files, text files, WordPerfect files, or the like. Such files are commonly distributed by way of communication medians, such as the Internet. Such content files are commonly posted onto web sites where such content files can be downloaded by users. In certain instances, money is charged for the ability to download the content files, and in other instances such downloading is permitted for free.
In certain instances, such content files are protected by more than one password. For example, .pdf files commonly have two passwords: a user password, and an owner password. If a party knows the owner password, then such party can print the content file, save the content file under another name, or in general have all rights of the content owners. For this reason, many content owners will specify a user password which upon use provides the user with much less rights with respect to such file. Common user privileges would be only to view such content file. The user would typically not have the ability to print, make copies, or to distribute such content file.
There are two common manners to avoid the protection of the .pdf file. The first manner to avoid the protection accorded the .pdf file is to “capture” the screen to the computer's clipboard. Each captured screen is then saved as a separate file and then the separate files are then consolidated into a single file. The second manner is to use a password cracker program. For .pdf files, a product entitled “Advanced PDF Password Recovery” is available from ElComSoft Proactive Software. Elcomsoft's software requires the recipient of the content file to enter the “user” password. Under normal circumstances a distributor of a password protected PDF file, must disclose the user or “open” password to the user so they can open and view the file. By doing so they expose the “Owner” password to attack by ElComsoft's password cracker. Elcomsoft's program will “not” work if the user and owner passwords are unknown.
Thus, a need exists to distribute a password protected content file without revealing a password to the recipient or user. It is to such a system and method that the present invention is directed. With respect to PDF files, an attribute of the present invention is that the recipient or user cannot learn either the user or the owner password. Thus, the recipient or user cannot use Elcomsoft's program to attack the owner password.